A Beginner’s Guide to Caring for Lobelia in Pots

Lobelia is a gorgeous flowering plant that adds a pop of color to gardens, hanging baskets, and containers. The dainty flowers come in shades of blue, purple, pink, red, and white. I love using lobelia in my patio pots and window boxes to trail over the edges.

Caring for lobelia as a container plant is easy once you understand a few basic needs. With proper soil, water, light, and fertilizer, your potted lobelias will thrive all season long.

Selecting the Best Pot for Lobelia

Lobelia grown in containers does best in pots that are wider than they are deep. Shallow pots that are 4-6 inches deep work nicely. Make sure the pot has drainage holes in the bottom to prevent soggy soil.

Plastic, terra cotta, ceramic, and wood containers all make good homes for lobelia. Match the pot size to the number of plants you want to grow. For example, you can fit around 5-7 lobelia plants in a 10-12 inch wide pot.

I recommend using pots with saucers to catch excess water and keep surfaces underneath clean Place pebbles or stones in the saucer to prevent the pots from sitting in water

The Right Soil Mix for Potted Lobelia

Since container plants are more prone to drying out, the soil needs to retain moisture but still drain well. An all-purpose potting mix amended with compost or peat moss provides the ideal balance.

You can also create your own lobelia potting soil by mixing

• 2 parts potting soil or compost
• 1 part perlite or vermiculite for drainage
• 1 part peat moss to help retain moisture

Make sure any potting mix is light and fluffy, not dense or compacted. Soil that compacts over time can block water and oxygen from reaching lobelia roots.

Planting Lobelia in Containers

Spring is the best time to plant lobelia in pots outdoors after the threat of frost has passed. Since lobelia is frost tender, wait until nighttime temps remain above 45°F.

Start by filling the containers about 2/3 full with moistened potting mix. Carefully remove lobelia plants from their small starter pots, loosening the roots before planting.

Set each lobelia plant in the pot, spacing them 4-6 inches apart. Add more potting mix around the root balls, filling up to 1 inch below the pot rim. Water thoroughly after planting.

Proper Light Conditions for Container Lobelia

Most types of lobelia flourish in full sun. At least 6 hours of direct sunlight per day keeps the plants flowering prolifically. However, in very hot climates, afternoon shade is beneficial.

Monitor pots in full sun to ensure the soil doesn’t dry out. Check soil moisture daily and water whenever the top inch becomes dry. Pots in partial shade may only need watering every 2-3 days.

If possible, rotate containers periodically so all sides of the plants receive even light exposure. This prevents lobelias from becoming leggy as they lean toward the light.

Watering Needs for Potted Lobelia

Since potting soil dries out faster than garden beds, lobelia containers require frequent watering. Pots in full sun may need daily watering in hot weather. Never let containers completely dry out.

Apply water slowly and deeply to moisten the entire soil ball. For hanging baskets, submerge the entire basket to soak the mix. For other pots, water until it drains from the bottom drainage holes.

The soil should be moist but not saturated between waterings. Sticking your finger into the top inch of mix is the best way to assess moisture levels.

Fertilizing Lobelia for Healthy Growth

Lobelia benefits from regular feeding to support flowering and vigorous growth. Use a liquid fertilizer made for blooming container plants every 2-4 weeks during spring and summer.

Some options are fish emulsion, compost tea, or a water-soluble plant food diluted to half strength. Always follow label directions for correct product use.

If you incorporated compost or composted manure into the original potting mix, your lobelia may not need fertilizing for the first month after planting. But potting soils become depleted over time.

Special Winter Care for Container Lobelia

Lobelia thrives in the cool weather of spring and fall but cannot tolerate frost or freezing temperatures. Container plants will die back with the first hard freeze.

To overwinter lobelia in pots, the plants need bright, cool conditions around 40-50°F and limited watering. This is difficult to provide indoors for most homes.

Instead, take cuttings in late summer to propagate new lobelia plants for the following spring. Either collect seeds at the end of the season or remove and discard dead lobelia plants from pots before winter.

Troubleshooting Common Lobelia Problems

With proper care, lobelia grown in containers is relatively trouble-free. But occasionally you may run into these issues:

• Leggy growth: Insufficient sunlight causes lobelias to become lanky as they stretch for light. Move pots into sunnier locations.

• Few flowers: Extreme heat and dry soil cause poor flowering. Provide afternoon shade and increase watering frequency.

• Wilting: Wilted, drooping leaves indicate a lack of water. Check soil and water pots if the top few inches are dry.

• Leaf spot/mold: Overly wet soil encourages fungal disease. Allow pots to dry between waterings and apply fungicide if needed.

• Aphids: These tiny pests suck sap from lobelia foliage. Knock them off with a strong spray of water or use insecticidal soap.